Moon's South Pole: New Discoveries from Chandrayaan-3

India's Chandrayaan-3 mission has made a groundbreaking discovery, revealing that the Moon’s south pole is electrically more active than scientists previously believed. The data collected from the lander Vikram shows a significantly denser plasma layer above the lunar surface, with electron densities ranging between 380 to 600 particles per cubic centimeter. These values are much higher than earlier estimates that relied on remote-sensing techniques.

Plasma, often referred to as the fourth state of matter, comprises charged particles like ions and free electrons. It behaves differently from ordinary gases, responding strongly to electromagnetic forces. The Moon’s thin plasma layer, also known as the lunar ionosphere, is formed by various processes, including solar wind and high-energy sunlight. Solar wind streams carry electrons and ions from the Sun, which interact with the Moon’s airless surface, contributing to the ionized environment.

The findings from the Radio Anatomy of the Moon Bound Hypersensitive ionosphere and Atmosphere–Langmuir Probe (RAMBHA-LP) are significant as they represent the first direct, low-altitude measurements of the lunar ionosphere. The data indicates that electrons near the lunar surface possess unexpectedly high energies, with kinetic temperatures measured between 3,000 and 8,000 Kelvin. This suggests a more energized plasma layer than previously understood.

Researchers noted that the plasma layer is not static; it varies depending on the Moon's position in its orbit around Earth. During lunar daylight, when the Moon is fully exposed to the Sun, the interaction between solar wind particles and the Moon’s sparse exosphere largely drives the changes. Conversely, when the Moon moves into Earth's geomagnetic tail, the plasma dynamics are influenced by charged particles flowing through that region.

Insights from this mission also indicate that molecules like carbon dioxide and water vapor may play a role in shaping the lunar ionosphere. The Lunar Ionospheric Model developed by the research team highlights the importance of molecular ions in forming the charged layer above the Moon’s surface.

Together, these findings provide crucial "ground truth" data for future lunar exploration, especially for missions targeting the Moon’s southern high latitudes. The RAMBHA-LP was developed by the Space Physics Laboratory at the Vikram Sarabhai Space Centre in Thiruvananthapuram, showcasing India's growing capabilities in space science and instrumentation.